Mysql怎么查询数据库连接状态

发布时间：2023-05-24 09:41:04 所属栏目：MySql教程来源：

导读：本文小编为大家详细介绍“Mysql怎么查询数据库连接状态”，内容详细，步骤清晰，细节处理妥当，希望这篇“Mysql怎么查询数据库连接状态”文章能帮助大家解决疑惑，下面跟着小编的思路慢慢深入，

本文小编为大家详细介绍“Mysql怎么查询数据库连接状态”，内容详细，步骤清晰，细节处理妥当，希望这篇“Mysql怎么查询数据库连接状态”文章能帮助大家解决疑惑，下面跟着小编的思路慢慢深入，一起来学习新知识吧。

查看显示所有数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| INVOICE |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)

mysql>

查看当前使用的数据库
mysql> select database();
+------------+
| database() |
+------------+
| INVOICE |
+------------+
1 row in set (0.00 sec)

mysql>

查看数据库使用端口
mysql> show variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3306 |
+---------------+-------+
1 row in set (0.00 sec)

查看当前数据库大小

例如，我要查看INVOICE数据库的大小，那么可以通过下面SQL查看

mysql> use information_schema
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select concat(round(sum(data_length)/(1024*1024),2) + round(sum(index_length)/(1024*1024),2),'MB') as 'DB Size'
-> from tables
-> where table_schema='INVOICE';
+-----------+
| DB Size |
+-----------+
| 7929.58MB |
+-----------+
1 row in set, 1 warning (0.00 sec)

查看数据所占的空间大小
mysql> use information_schema;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select concat(round(sum(data_length)/(1024*1024),2),'MB') as 'DB Size'
-> from tables
-> where table_schema='INVOICE';
+-----------+
| DB Size |
+-----------+
| 6430.26MB |
+-----------+
1 row in set, 1 warning (0.00 sec)

mysql>

查看索引所占的空间大小
mysql> select concat(round(sum(index_length)/(1024*1024),2),'MB') as 'DB Size'
-> from tables
-> where table_schema='INVOICE';
+-----------+
| DB Size |
+-----------+
| 1499.32MB |
+-----------+
1 row in set, 1 warning (0.13 sec)

mysql>

（编辑：汽车网）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!